This invention relates to mechanisms for opening and closing garage doors automatically and, more particularly, to an automatic locking and unlocking mechanism for use with an automatic garage door opening system wherein a garage door pivoted for opening and closing has an operating arm of an automatic garage door opener connected to a top edge thereof for opening and closing the door comprising, a locking bar attached to the garage door for sliding motion between an extended locked position and a retracted unlocked position, the locking bar being disposed to engage an area peripheral to the garage door only when in the extended locked position; a mounting plate carrying the locking bar for sliding movement between the extended locked position and the retracted unlocked position; biasing means for urging the locking bar to the extended and locked position, the biasing means comprising a spring connected between the mounting plate and the locking bar to urge the locking bar towards the extended locked position; a pivot plate mounted to the top of the garage door, the pivot plate having a pair of vertical members with a pivot pin disposed between them; a lock-lifting arm disposed between the vertical members, the lock-lifting arm having a first hole therethrough adjacent one end thereof having the pivot pin disposed therethrough, the lock-lifting arm having a second hole therethrough adjacent a second end thereof opposite the one end; a connecting cable connected between the second hole in the lock-lifting arm and the locking bar; and, a slider member disposed between the vertical members in combination with the lock-lifting arm for sliding movement therebetween, the slider member having the operating arm of the automatic garage door opener connected thereto for sliding the slider member between the pair of vertical members during opening and closing of the garage door, the slider member having lifting means operably connected to the lock-lifting arm for lifting the second end of the lock-lifting arm when the slider member is slid between the vertical members on the pivot pin from a closed and locked position towards an open and unlocked position and for lowering the second end of the lock-lifting arm when the slider member is slid between the vertical members on the pivot pin from the open and unlocked position to the closed and locked position, the slider member having control means for preventing the operating arm of the automatic garage door opener from lifting the top of the garage door to open the garage door until the slider member has slid from the closed and locked position to the open and unlocked position and for preventing the slider member from sliding from the open and unlocked position to the closed and locked position until the operating arm of the automatic garage door opener has lowered the top of the garage door to a fully closed position.
Garage doors equipped with automatic garage door openers are becoming a common accessory in many modern homes due to the convenience and security of remaining in the car while opening and closing the garage door with the simple push of a button. As depicted in simplified form in FIG. 1, the typical automatic garage door opener includes an opening/closing mechanism 10 which drives a chain 12 (or a worm drive in some models) as a result of signals from a button (in the garage) or a radio frequency opener (from a car). A releasable connecting member 14 attaches an operating arm 16 between the chain 12 and a pivot plate 18 attached to the top center of the garage door 20. To open the garage door 20, the mechanism 10 operates the chain 12 in a counter-clockwise direction to move the connecting member 14 and operating arm 16 from left to right as the figure is viewed. The mechanism 10 pulls the top of the garage door 20 up and backwards to open it about its pivot point (not shown). To close the door 20, the mechanism operates in just the opposite fashion to push the top of the door 20 forward and down.
Unfortunately, automatic garage door openers are not locking mechanism such as a padlock and hasp or a dead-bolt lock, it is relatively easy to overcome the force exerted by the automatic mechanical opening device and gain entry to the garage--and typically to the inside of the house through an unlocked door into the garage as well. Additionally, since the automatic garage door opener engages the garage door only at the top, even if the force of the opening device cannot be overcome in a particular installation, there remains sufficient flex in the garage door at the bottom to allow entry to the garage by prying up the garage door at one corner. Also, inherent in automatic openers is a certain amount of free play in the carriage and arm connections which aid in prying up the garage door. Once inside, of course, a thief can simply pull a release on the actuating arm that connects the top of the garage door to the operating chain or worm drive and then lift the garage door without any impeding force whatsoever.
Since manually locking the garage door before and after each opening and closing eliminates all the convenience and security benefits of the automatic opening device, there is a clear need for a locking mechanism which secures the garage door automatically and in conjunction with the automatic opener.
Heretofore, inventors have created several types of camactivated latching devices which are installed between the carriage and track as in U.S. Pat. Nos. 3,435,558 of Kruse and 3,526,479 of Delaney. While apparently preventing free play in the carriage, these devices do not deal with the inherent flex in the garage door and free play in the arm connections.
The invention of Curtis (U.S. Pat. No. 2,589,479) utilizes a sliding bolt lock which passes over the top edge of the garage door and engages a door frame keeper to prevent unauthorized raising of the garage door. While this design is apparently effective with the roll-up type of garage door which is popular on the east coast of the United States, a single slab door rotating about a center pivot point is a cheaper and more popular instalation on the west coast. Moreover, the keyed outside handle provides a means of entry for any knowledgeable burglar. Additionally, the bell crank arm and companion parts make it awkward and unduly expensive.
Several inventions using automatic garage door locks that function in combination with the carriage movement are illustrated in U.S. Pat. Nos. 3,708,917 (Streeter), 4,442,631 (Weber), and 4,597,224 (TUCKER). These devices vary in the type of delaying mechanism used to unlock the garage door prior to the beginning of its opening cycle. In each case, however, carefully aligned pivot parts and accurately tensioned springs are required, as well as major alterations to the existing garage door operating equipment. These delicately adjusted devices are easily put out of alignment and create recurring maintenance problems. In addition to being expensive to buy, the expertise and the costs involved in altering the existing garage door operating devices put these devices out of the range of the average home owner.
Pat. No. 4,805,344 to Hrboka discloses a much simpler design (depicted in FIG. 2) which does not require substantial alterations of existing equipment. The end of the operating arm 16' connected to the pivot plate 18 has a slot 22 rather than a pivot hole as in the apparatus of FIG. 1. Additionally, there is a heavy deadbolt bar 24 slidably mounted at the bottom of the door 20 which engages a hole (not shown) in the garage floor at the bottom of the door 20 to prevent the door 20 from being raised as described above. The bar 24 is connected to the connecting member 14 through a guide 26 by a connecting cable 28. Thus, as the connecting member 14 moves from left to right as the figure is viewed to raise the door 20, the pivot pin 30 moves along the slot 22 while the cable 28 pulls the bar 24 from its locking hole in the floor. Once the bar 24 is free, the end of the slot 22 pulls on the pivot pin 30 and pulls the door 20 up as in the prior art mechanism of FIG. 1. While the Hrboka apparatus appears to be adequate for its intended use on paper, in actual practice it has several shortcomings that prevent it from being the answer to the problem that the inventor evidently anticipated it would be. For one thing, it relies upon gravity alone to engage the locking mechanism (i.e. lower the bar 24 into its locking hole) and any impediment such as rust or debris may be sufficient to interfere with the locking engagement thereof. Furthermore, upon closing the design lacks any sort of mechanism to keep the lock retracted (i.e. the bar 24 raised) until the garage door closing cycle is completed and the door 20 is fully closed and ready for the bar 24 to engage its locking hole. As a result, the bar tends to drop early and drag on the garage floor with each closing. Not only does this cause damage to the floor and bar 24; but, if the drag on the bar 24 is too great, the automatic opener's pressure safety mechanism (included in most automatic garage door openers to prevent closing the door with something under the door) may be activated and abort the closure of the garage door. Furthermore, since the Hrboka apparatus employs only the simple slot 22 as its "delaying" mechanism, there is no positive control of the door 20 during the opening and closing as in the case of the prior art mechanism of FIG. 1 where there is a pin in a hole at the pivot plat 18 which affords a much greater control of the door 20 during opening and closing. Thus, in the Hrboka apparatus, the door can move freely back and forth in the slot causing substantial stress, wear, and premature aging of the door 20 and the supporting door frame and pivot assembly (not shown) as well as the slot 22 and pivot pin 30.
Wherefore, it is an object of this invention to provide a safe, dependable, easy to install, and inexpensive garage door locking mechanism for automatic garage doors which works simultaneously and in conjunction with an existing garage door opening system.
It is another object of this invention to provide a garage door locking mechanism for automatic garage doors which prevents unauthorized entry into the garage as a result of the inherent flex in the door and free play in the carriage and arm connections by using a bolting system into the floor of the garage at the bottom of the garage door.
It is yet another object of this invention to provide a garage door locking mechanism for automatic garage doors which does not require major alterations to the existing automatic opening system.
It is still another object of this invention to provide a garage door locking mechanism for automatic garage doors which does not require delicate adjustments and constant maintenance in order to function on a reliable, on-going basis.
It is a further object of this invention to provide a garage door locking mechanism for automatic garage doors which has positive spring-actuated lock engagement to insure proper locking of the door each and every time the door is closed.
It is a still further object of this invention to provide a garage door locking mechanism for automatic garage doors which retracts the lock prior to the door beginning its opening cycle and retains the locking bolt in the fully retracted position until the garage door is fully closed.
It is yet a further object of this invention to provide a garage door locking mechanism for automatic garage doors which exerts positive control over the garage door during its entire opening and closing cycle.
Further objects and benefits of the invention will become apparent from the detailed description which follows hereinafter when taken in conjunction with the drawing figures which accompany it.